Rank-Taylor IRTAL 3 100mm F0.7

Thermal Imager Objective Lens

This item is a very large and very fast germanium objective lens for a thermal imager or thermal imaging camera. The focal length is 100mm, and the maximum aperture is F0.7 The front element is more than 14cm in diameter. Made by Rank-Taylor in the UK.

There is an aperture adjustment ring, with settings from F0.7 through to F4. There is a focus ring with settings from 5 feet to infinity. The body has a threaded rear mounting and a matching adaptor ring is fitted.

The condition is very good, but not perfect. As often seen with germanium lenses, there are spots on the front surface (near to the lens edge) where the anti-reflection coating has corroded. We have tested the lens and find no obvious image degradation.